<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <script>
        for(var j=0;j<5;j++){
            for(var i=0;i<j;i++){
                document.write("*");
            }
            document.write("<br/>");
        }
    </script>
</body>
</html>